Three-dimensional polymeric strand netting, dies, and methods of making the same

ABSTRACT

Three-dimensional polymeric strand netting, wherein a plurality of the polymeric strands are periodically joined together in a regular pattern at bond regions throughout the array, wherein a majority of the polymeric strands are periodically bonded to at least two (three, four, five, six, or more) adjacent polymeric strands, and wherein no polymeric strands are continuously bonded to a polymeric strand. Three-dimensional polymeric strand netting described herein have a variety of uses, including wound care, tapes, filtration, absorbent articles, pest control articles, geotextile applications, water/vapor management in clothing, reinforcement for nonwoven articles, self bulking articles, floor coverings, grip supports, athletic articles, and pattern coated adhesives.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional application of pending prior U.S.application Ser. No. 14/349,104, filed Apr. 2, 2014 (now allowed), whichis a National Stage Entry under PCT/US2012/057900, filed Sep. 28, 2012,which claims the benefit of U.S. Provisional Patent Application No.61/543,481, filed Oct. 5, 2011, U.S. the disclosure of which isincorporated by reference herein in its entirety.

BACKGROUND

Polymeric nets are used for a wide variety of applications, includingreinforcement of paper articles or cheap textiles (e.g., in sanitarypaper articles, paper cloth, and heavy duty bags), non-woven upholsteryfabrics, window curtains, decorative netting, wrapping material,mosquito netting, protective gardening netting against insects or birds,backing for growing of grass or plants, sport netting, light fishingnetting, and filter materials.

Extrusion processes for making polymeric nets are well known in the art.Many of these processes require complex dies with moving parts. Many ofthese processes can only be used to produce relatively thick nettingwith relatively large diameter strands and/or relatively large mesh oropening sizes.

Polymeric netting can also be obtained from films by slitting a patternof intermittent lines, which are mutually staggered, and expanding theslit film while stretching. This process tends to produce netting of arelatively large mesh and with relatively weak cross-points.

There exists a need for a relatively simple and economical process forproducing polymeric nettings.

SUMMARY

In one aspect, the present disclosure describes a three-dimensionalpolymeric strand netting, wherein a plurality of the polymeric strandsare periodically joined together in a regular pattern at bond regionsthroughout the netting, wherein at least some (in some embodiments, amajority by number) of the polymeric strands are periodically bonded toat least three (, four, five, six, or more) adjacent polymeric strands,and wherein no polymeric strands are continuously bonded to anotherpolymeric strand. In some embodiments, the at least three polymericstrands will be respectively part of first, second, and third arrays ofpolymeric strands. In some embodiments, the arrays of polymeric strandsare formed from the same polymer, in other embodiments the arrays ofpolymeric strands are formed of two or more polymers. In someembodiments, at least some of the arrays of polymeric strands aretwo-component strands. In some embodiments that have two-componentstrands, those strands have a core of a first polymeric material and asheath of a second, different polymeric material. In some embodimentswhere some of the polymeric strands have a core/sheath arrangement, atleast some of these cores have at least two (in some embodiments atleast 3 or more) sheaths).

In another aspect, the present disclosure describes a method of making athree-dimensional netting, the method comprising:

providing an extrusion die comprising a plurality of shims positionedadjacent to one another, the shims together defining at least a firstcavity and a dispensing surface, wherein the dispensing surface has afirst array of first dispensing orifices and second array of seconddispensing orifices positioned adjacent to each other, alternating witha third array of third dispensing orifices; wherein the plurality ofshims comprises a plurality of a repeating sequence of shims, whereinthe repeating sequence comprises a shim that provides a fluid passagewaybetween a cavity and one of the first dispensing orifices, a shim thatprovides a fluid passageway between a cavity and one of the seconddispensing orifices, and a shim that provides a fluid passageway betweena cavity and one of the third dispensing orifices; and

dispensing polymeric strands from at least one of the first, second, orthird arrays of dispensing orifices at a first strand speed whilesimultaneously dispensing polymeric strands from at least one of theother arrays at a second strand speed, wherein the first strand speed isat least 2 (in some embodiments, in a range from 2 to 6, or even 2 to 4)times the second strand speed to provide the three-dimensional netting.

In another aspect, the present disclosure describes an extrusion diecomprising a plurality of shims positioned adjacent to one another, theshims together defining at least a first cavity and a dispensingsurface, wherein the dispensing surface has a first array of firstdispensing orifices, a second array of second dispensing orifices, and athird array of third dispensing orifices, the third array being disposedgenerally between the first and second arrays; wherein the plurality ofshims comprises a plurality of a repeating sequence of shims, whereinthe repeating sequence comprises a shim that provides a fluid passagewaybetween a cavity and one of the first dispensing orifices, a shim thatprovides a fluid passageway between a cavity and one of the seconddispensing orifices, and a shim that provides a fluid passageway betweena cavity and one of the third dispensing orifices. In some embodiments,the extrusion die further comprises a fourth array (or more) of fourth(or more) dispensing orifices. In some embodiments, the orifices of eachrespective array are collinear with the other orifices of that arrayacross the face of the dispensing surface. Typically, orifices within anarray are spaced apart by at least two times greater than the width ofthe orifices, to prevent continuous bonding of two strands emerging fromthe same array. Typically, the arrays of dispensing orifices areparallel to, but offset from each other across the face of thedispensing surface. Typically, this offset is not greater than theheight of adjacent orifices so that strands emerging from differentarrays will bond in a thickness direction. A photograph of an exemplarydispensing surface having arrays that satisfy the just describedcriteria is shown in FIG. 13.

In some embodiments of the die, the shims further define at least asecond cavity, wherein the repeating sequence of shims provide a fluidpassageway from both the first and second cavities to one of the arrays,and wherein the first cavity is supplied with a first polymer and thesecond cavity is supplied with a second polymer so as to dispensetwo-component strands from that array. In some such embodiments, thetwo-component strands have a core/sheath arrangement.

Three-dimensional polymeric strand netting described herein have avariety of uses, including wound care and other medical applications(e.g., elastic bandage-like material, surface layer for surgical drapesand gowns, and cast padding), tapes (including for medicalapplications), filtration, absorbent articles (e.g., diapers andfeminine hygiene products) (e.g., as a layer(s) within the articlesand/or as part of an attachment system for the articles), pest controlarticles (e.g., mosquito nettings), geotextile applications (e.g.,erosion control textiles), water/vapor management in clothing,reinforcement for nonwoven articles (e.g., paper towels), self bulkingarticles (e.g., for packaging) where the netting thickness is increasedby stretching nettings with first strands have average first yieldstrength, and wherein the second strands have an average second yieldstrength that is different (e.g., at least 10 percent different) thanthe first yield strength, floor coverings (e.g., rugs and temporarymats), grip supports for tools, athletic articles, etc., electrodes inlight weight lead acid batteries, and pattern coated adhesives.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of shim particularly suited to form a repeatingsequence of shims capable of forming a three-dimensional polymericstrand netting described herein;

FIG. 2 is a plan view of another shim particularly suited to form arepeating sequence of shims capable of forming a three-dimensionalpolymeric strand netting described herein;

FIG. 3 is a detail view of the section referenced as “detail 3” in FIG.2;

FIG. 4 is a plan view of another shim particularly suited to form arepeating sequence of shims capable of forming a three-dimensionalpolymeric strand netting described herein;

FIG. 5 is a plan view of another shim particularly suited to form arepeating sequence of shims capable of forming a three-dimensionalpolymeric strand netting described herein;

FIG. 6 is a detail view of the section referenced as “detail 6” in FIG.5;

FIG. 7 is an exploded perspective assembly drawing of a repeatingsequence of shims employing the shims of FIGS. 1, 2, 4, and 5;

FIG. 8 is a detail view of the section referenced as “detail 8” in FIG.7;

FIG. 9 is an exploded perspective view of a mount suitable for anextrusion die composed of multiple repeats of the repeating sequence ofshims of FIG. 7;

FIG. 9A is a perspective view of the mount of FIG. 9 in an assembledstate;

FIG. 10 is a schematic perspective view of a die producing multi-layernetting described herein;

FIG. 11 is a perspective view of an exemplary article described hereinhaving ribbon regions and multi-layer netting regions;

FIG. 12 is a perspective view of an exemplary article having a set ofstrands in a multi-layer netting, bonded to a substrate;

FIG. 13 is a digital optical image at 10× of a front view of adispensing surface of a die, showing dispensing orifices at threedifferent levels in the direction to both the machine direction and thecross-direction of the extruded multi-layer netting the die can produce;and

FIG. 14 is a digital optical image at 10× of an exemplary nettingdescribed herein.

DETAILED DESCRIPTION

The dispensing surface comprises at least three arrays of orifices.These arrays are typically extruded at a strand speed difference of atleast two times to create the discontinuous bonds in the net network.For example, the top and bottom array of strands can be extruded at aspeed that is two times greater than the center layer to create thebonds in the net between arrays. As an additional example, the centerlayer can be extruded two times faster than the top and bottom layers tocreate the bonds in the net between arrays. These orifices are typicallycollinear within the array and are offset with other orifice arrays ofthe dispensing surface. The cross direction spacing between orificeswithin a given array is typically at least twice the width of theorifice, such that the extruded strands, from the array of strandsextruded at the same speed, do not form a continuous bond. The spacingbetween arrays of orifices typically overlap or nearly overlap, suchthat the resultant arrays create zones of strands that in the thicknessdirection of the netting structure. Strands in each zone bond to strandsin an adjacent zone(s). Typically, the spacing is not greater than theheight of adjacent orifices. It is envisioned that the arrays do notneed to be collinear, but may form other patterns to create themulti-layer netting.

In some embodiments, the plurality of shims comprises a plurality of atleast one repeating sequence of shims that includes shims that provide apassageway between a first and second cavity and the first dispensingorifices. In some of these embodiments, there will be additional shimsthat provide a passageway between the first and/or the second cavity,and/or a third (or more) cavity and second dispensing orifices.Typically, not all of the shims of dies described herein havepassageways, as some may be spacer shims that provide no passagewaybetween any cavity and a dispensing orifice. In some embodiments, thereis a repeating sequence that further comprises at least one spacer shim.The number of shims providing passageway to the first dispensingorifices may be equal or unequal to the number of shims providing apassageway to the second dispensing orifices, which may be equal orunequal to the number of shims providing a passageway to the thirddispensing orifices.

In some embodiments, extrusion dies described herein include a pair ofend blocks for supporting the plurality of shims. In these embodimentsit may be convenient for one or all of the shims to each have one ormore through-holes for the passage of connectors between the pair of endblocks. Bolts disposed within such through-holes are one convenientapproach for assembling the shims to the end blocks, although theordinary artisan may perceive other alternatives for assembling theextrusion die. In some embodiments, the at least one end block has aninlet port for introduction of fluid material into one or both of thecavities.

In some embodiments, the shims will be assembled according to a planthat provides a repeating sequence of shims of diverse types. Therepeating sequence can have diverse numbers of shims per repeat. For afirst example, a four-shim repeating sequence is described below inconnection with FIG. 7. When that four-shim repeating sequence isproperly provided with molten polymer, it extrudes a netting formed fromthree sets of polymeric strands that, although they have bonds betweenthe sets of strands, in general form different zones within thethickness direction of the netting.

Exemplary passageway cross-sectional shapes include square andrectangular shapes. The shape of the passageways within, for example, arepeating sequence of shims, may be identical or different. For example,in some embodiments, the shims that provide a passageway between thefirst cavity and a first dispensing orifice might have a flowrestriction compared to the shims that provide a conduit between thesecond cavity and a second dispensing orifice. The width of the distalopening within, for example, a repeating sequence of shims, may beidentical or different. For example, the portion of the distal openingprovided by the shims that provide a conduit between the first cavityand a first dispensing orifice could be narrower than the portion of thedistal opening provided by the shims that provide a conduit between thesecond cavity and a second dispensing orifice.

In some embodiments, the assembled shims (conveniently bolted betweenthe end blocks) further comprise a manifold body for supporting theshims. The manifold body has at least one (or more (e.g., two or three,four, or more)) manifold therein, the manifold having an outlet. Anexpansion seal (e.g., made of copper or alloys thereof) is disposed soas to seal the manifold body and the shims, such that the expansion sealdefines a portion of at least one of the cavities (in some embodiments,a portion of both the first and second cavities), and such that theexpansion seal allows a conduit between the manifold and the cavity.

Typically, the passageway between cavity and dispensing orifice is up to5 mm in length. Sometimes the fluid passageways leading to one array hasgreater fluid restriction than the fluid passageways leading to one ormore of the other arrays.

In some embodiments, for extrusion dies described herein, each of thedispensing orifices of the first and the second arrays have a crosssectional area, and each of the dispensing orifices of the first arrayshas an area different than that of the second array.

Typically, the spacing between arrays of orifices overlap or nearlyoverlap. The spacing between array orifices is greater than theresultant diameter of the strand after extrusion. This diameter iscommonly called die swell. This spacing between orifices is greater thanthe resultant diameter of the strand after extrusion leads to thestrands repeatedly colliding with each other to form the repeating bondsof the netting. If the spacing between orifice arrays is too great thestrands will not collide with each other and will not form the netting.Typically, the spacing between orifices of the same array is greaterthan two times the width of the orifice, to prevent continuous bondingof strands extruded at the same speed.

The shims for dies described herein typically have thicknesses in therange from 50 micrometers to 125 micrometers, although thicknessesoutside of this range may also be useful. Typically, the fluidpassageways have thicknesses in a range from 50 micrometers to 750micrometers, and lengths less than 5 mm (with generally a preference forsmaller lengths for decreasingly smaller passageway thicknesses),although thicknesses and lengths outside of these ranges may also beuseful. For large diameter fluid passageways several smaller thicknessshims may be stacked together, or single shims of the desired passagewaywidth may be used.

The shims are tightly compressed to prevent gaps between the shims andpolymer leakage. For example, 12 mm (0.5 inch) diameter bolts aretypically used and tightened, at the extrusion temperature, to theirrecommended torque rating. Also, the shims are aligned to provideuniform extrusion out the extrusion orifice, as misalignment can lead tostrands extruding at an angle out of the die which inhibits desiredbonding of the net. To aid in alignment, an alignment key can be cutinto the shims. Also, a vibrating table can be useful to provide asmooth surface alignment of the extrusion tip.

The size (same or different) of the strands can be adjusted, forexample, by the composition of the extruded polymers, velocity of theextruded strands, and/or the orifice design (e.g., cross sectional area(e.g., height and/or width of the orifices)). For example, an orificein, for example, the first array that is 3 times greater in area than anorifice in, for example, the second array can generate a netting withequal first and second strand sizes while meeting the velocitydifference between adjacent strands.

In general, it has been observed that the rate of strand bonding isproportional to the extrusion speed of the faster strand. Further, ithas been observed that this bonding rate can be increased, for example,by increasing the polymer flow rate for a given orifice size, or bydecreasing the orifice area for a given polymer flow rate. It has alsobeen observed that the distance between bonds (i.e., strand pitch) isinversely proportional to the rate of strand bonding, and proportionalto the speed that the netting is drawn away from the die. Thus, it isbelieved that the bond pitch and the netting basis weight can beindependently controlled by design of the orifice cross sectional area,the takeaway speed, and the extrusion rate of the polymer. For example,relatively high basis weight nettings, with a relatively short bondpitch can be made by extruding at a relatively high polymer flow rate,with a relatively low netting takeaway speed, using a die with arelatively small strand orifice area.

Some of the embodiments of dies according to the present disclosure havean array of vestibules in which a core/sheath strand is formed. Suchdies can include a plurality of shims comprising a plurality of arepeating sequence of shims. Such a repeating sequence can include shimsthat provide a fluid passageway between the first cavity and one of thevestibules, shims that provide a second passageway extending from thesecond cavity to the same vestibule, and shims that provide a thirdpassageway extending from the second cavity to the same vestibule,wherein each of the second and third passageways are on opposite sidesof the first passageway, and each of the second and third passagewayshas a dimension larger than the first passageway at the point where thefirst passageway enters the vestibule. This allows the flows from thesecond and third passageways to encapsulate the material entering thevestibule from the first passageway. Obtaining good encapsulation of thecore material entering from the first passageway depends in part on themelt viscosity of the sheath material. In general, lower melt viscosityof the sheath material improves the encapsulation of the core material.Further, the encapsulation depends in part on the degree to which thesecond and third passageways have a dimension larger than the firstpassageway at the point when they enter the vestibule. In general,increasing the degree by which that dimension is larger for the secondand third passageways relative to same dimension for the firstpassageway will improve the encapsulation of the core material. Goodresults are obtained when the dimensions of the passageways andpressures within the cavities are manipulated so that the flow speed ofthe sheath materials within the vestibule and the flow speed of the corematerials within the vestibule are close to one another. Additionalinformation about shim based dies that form netting where at least someof the strands have a core/sheath arrangement can be found inapplication having U.S. Ser. No. 61/530,521, filed Sep. 2, 2011, thedisclosure of which is incorporated herein by reference.

In practicing methods described herein, the polymeric materials might besolidified simply by cooling. This can be conveniently accomplishedpassively by ambient air, or actively by, for example, quenching theextruded first and second polymeric materials on a chilled surface(e.g., a chilled roll). In some embodiments, the first and/or secondand/or third polymeric materials are low molecular weight polymers thatneed to be cross-linked to be solidified, which can be done, forexample, by electromagnetic or particle radiation. In some embodiments,it is desirable to maximize the time to quenching to increase the bondstrength.

Optionally, it may be desirable to stretch the as-made netting.Stretching may orientate the strands, and has been observed to increasethe tensile strength properties of the netting. Stretching may alsoreduce the overall strand size, which may be desirable for applicationswhich benefit from a relatively low basis weight. As an additionalexample, if the materials and the degree of stretch, are chosencorrectly, the stretch can cause some of the strands to yield whileothers do not, tending to form loft (e.g., the loft may be createdbecause of the length difference between adjacent bonded netting strandsor by curling of the bonds due to the yield properties of the strandsforming the bond). The attribute can be useful for packagingapplications where the material can be shipped to package assembly in arelatively dense form, and then lofted, on location. The loftinessattribute can also be useful as the loop for hook and loop attachmentsystems, wherein the loft created with strands enables hook attachmentto the netting strands. As a second additional example, if the materialsof the first and second sets of strands are of different strength,cross-machine direction stretching can cause one strand to stretch andthe second set of strand to not stretch. This can be useful to createfor example, elastic strands which provide machine direction elasticity,which are connected to small, oriented strands, which purpose is to holdthe elastic strands in place. In some embodiments, netting could be madewith cross-direction elasticity with relatively small strands that areelastic, connected to relatively large strands that are inelastic.

Referring now to FIG. 1, a plan view of shim 5340 is illustrated. Shim5340 has first aperture 5360 a, second aperture 5360 b, and thirdaperture 5360 c. When shim 5340 is assembled with others as shown inFIG. 7, aperture 5360 a will help define first cavity 5362 a, aperture5360 b will help define second cavity 5362 b, and aperture 5360 c willhelp define third cavity 5362 c. As will be discussed with moreparticularity below, molten polymer in cavities 5362 a and 5362 c can beextruded in a strand with a multilayer arrangement, and molten polymerin cavity 5362 b can be extruded as a simple strand so as to form athree-dimensional polymeric strand netting described herein. Passageways5368 a, 5368 b, and 5368 c cooperated with analogous passageways onadjacent shims to allow passage from cavities 5362 a, 5362 b, and 5362 cto the dispensing surfaces of the appropriate shims when the shims areas shown in FIG. 7.

Shim 5340 has several holes 47 to allow the passage of e.g. bolts tohold shim 5340 and others to be described below into an assembly. Shim5340 also has dispensing surface 5367, and in this particular embodimentdispensing surface 5367 has indexing groove 5380 which can receive anappropriately shaped key to ease assembling diverse shims into a die.The shim may also have identification notch 5382 to help verify that thedie has been assembled in the desired manner. This embodiment hasshoulders 5390 and 5392 which can assist in mounting the assembled diein a mount of the type shown in FIG. 9.

Referring now to FIG. 2, a plan view of shim 5440 is illustrated. Shim5440 has first aperture 5460 a, second aperture 5460 b, and thirdaperture 5460 c. When shim 5440 is assembled with others as shown inFIG. 7, aperture 5460 a will help define first cavity 5362 a, aperture5460 b will help define second cavity 5362 b, and aperture 5460 c willhelp define third cavity 5362 c. This embodiment has shoulders 5490 and5492 which can assist in mounting the assembled die in a mount of thetype shown in FIG. 9.

Referring now to FIG. 3, a detail view of the section referenced as“detail 3” in FIG. 2, is illustrated. Analogous to shim 5340, shim 5440has dispensing surface 5467, and in this particular embodiment thedispensing surface 5467 has indexing groove 5480. It might seem thatthere is no path from cavity 5362 c to dispensing orifice 5466, via, forexample, passageway 5468 c, but this is an illusion—the flow has a routein the perpendicular-to-the-plane-of-the-drawing dimension when therepeating sequence of FIG. 7 is completely assembled.

Referring now to FIG. 4, a plan view of shim 5640 is illustrated. Shim5640 has first aperture 5660 a, second aperture 5660 b, and thirdaperture 5660 c. When shim 5640 is assembled with others as shown inFIG. 7, aperture 5660 a will help define first cavity 5362 a, aperture5660 b will help define second cavity 5362 b, and aperture 5660 c willhelp define third cavity 5362 c. Shim 5640 has dispensing surface 5667,and in this particular embodiment dispensing surface 5667 has indexinggroove 5680 which can receive an appropriately shaped key to easeassembling diverse shims into a die. The shim may also haveidentification notch 5682 to help verify that the die has been assembledin the expected manner. This embodiment has shoulders 5690 and 5692which can assist in mounting the assembled die in a mount of the typeshown in FIG. 9. This shim may appear at first glance to be identical toshim 5340 in FIG. 1, however there are slight differences in thepassageways 5668 a and 5668 b compared with passageways 5368 a and 5368b to allow for robust movement of molten polymer from the cavities thedispensing surfaces of the several shims.

Referring now to FIG. 5, a plan view of a shim 5740 is illustrated. Shim5740 has first aperture 5760 a, second aperture 5760 b, and thirdaperture 5760 c. When shim 5740 is assembled with others as shown inFIG. 7, aperture 5760 a will help define first cavity 5362 a, aperture5760 b will help define second cavity 5362 b, and aperture 5760 c willhelp define third cavity 5362 c. This embodiment has shoulders 5790 and5792 which can assist in mounting the assembled die in a mount of thetype shown in FIG. 9.

Referring now to FIG. 6, a detail view of the section referenced as“detail 6” in FIG. 5, is illustrated. Analogous to shim 5340, shim 5740has dispensing surface 5767, and in this particular embodimentdispensing surface 5767 has indexing groove 5780. It might seem thatthere is no path from cavity 5362 a to dispensing orifice 5766 a, via,for example, passageway 5768 a, nor a path from cavity 5362 b todispensing orifice 5766 b, via, for example, passageway 5768 b, but thisis an illusion—the flow has a route in theperpendicular-to-the-plane-of-the-drawing dimension when the repeatingsequence of FIG. 7 is completely assembled

Referring now to FIG. 7, an exploded perspective assembly drawing of arepeating sequence of shims employing the shims of FIGS. 1, 2, 4, and 5is illustrated. Referring now to FIG. 8, a detail view of the sectionreferenced as “detail 8” in FIG. 7 is illustrated. In the particularillustrated embodiment, the repeating sequence includes, from bottom totop as the drawing is oriented, one instance of shim 5340, one instanceof shim 5440, one instance of shim 5640, and one instance of shim 5740.In this view, it can be appreciated how a strand of a single materialemerges from the egress provided dispensing orifice 5466, and how twodifferent materials emerge from the closely spaced dispensing orifices5766 a and 5766 b. For this configuration collisions between strands toform the three zones of net can be created by extruding 5466 strand atan extrusion speed that is at least two times different from strands5766 a and 5766 b.

Referring now to FIG. 9, an exploded perspective view of a mount 5230suitable for an extrusion die composed of multiple repeats of therepeating sequence of shims of FIG. 7 is illustrated. Mount 5230 isparticularly adapted to use shims 5340, 5440, 5640, and 5740 is shown inFIGS. 1, 2, 4 and 5. However for visual clarity, only a single instanceof shim 5440 is shown in FIG. 9. The multiple repeats of the repeatingsequence of shims of FIG. 7 are compressed between two end blocks 5244 aand 5244 b. Conveniently, through bolts can be used to assemble theshims to the end blocks 5244 a and 5244 b, passing through holes 47 inshims 5340 et al.

In this embodiment, inlet fittings 5250 a and 5250 b, and 5250 c providea flow path for three streams of molten polymer through the end blocks5244 a and 5244 b to the cavities 5362 a, 5362 b, and 5362 c.Compression blocks 5204 have a notch 5206 that conveniently engages theshoulders on the shims, e.g., 5490 and 5492 on 5440. When mount 5230 iscompletely assembled, compression blocks 5204 are attached by, e.g.machine bolts to backplates 5208. Holes are conveniently provided in theassembly for the insertion of cartridge heaters 52.

Referring now to FIG. 9A, a perspective view of the mount 5230 of FIG. 9is illustrated in a partially assembled state. A few shims, for example,5440 are in their assembled positions to show how they fit within themount 5230, but most of the shims that would make up an assembled diehave been omitted for visual clarity.

Referring now to FIG. 10, a partial schematic perspective view of die1030 producing multi-layer netting is illustrated. The view is partialbecause suitable end blocks have been omitted so that first cavity 1062a, second cavity 1062 b, and third cavity 1062 c can be seen. In thisschematic view, first strands 1070 a are being extruded from an array offirst dispensing orifices 1066 a, second strands 1070 b are beingextruded from an array of second dispensing orifices 1066 b, and thirdstrands 1070 c are being extruded from an array of third dispensingorifices 1066 c. In this view, both first strands 1070 a and secondstrands 1070 b are the ones being dispensed at a first strand speedwhich is at least 2 times the second strand speed at which third strands1070 c are being extruded. A three-dimensional netting is being formed.

Referring now to FIG. 11, a perspective view of exemplary articledescribed herein 1101 is illustrated. The present disclosure alsoprovides an article comprising one or more three-dimensional netting asdescribed herein, with a ribbon region disposed adjacent to or therebetween. Typically, the netting and ribbon region are integral. Thepresent disclosure also provides an article comprising two nettingregions described herein, each disposed between two ribbon regions.Typically, the netting and ribbon regions are integral. An example isshown in FIG. 11, where netting regions 1198 a and 1198 b, eachcomprising first strands 1170 a, second strands 1170 b, and thirdstrands 1170 c, are disposed between and connected to ribbon regions1199 a, 1199 b, and 1198 c. Ribbon regions 1199 a, 1199 b, and 1199 ccan be formed by constructing a portion of the die with a repeatingsequence of shims all connected to a single one of the cavities.

Referring now to FIG. 12, a perspective view of exemplary article 1201is illustrated. Article 1201 comprises netting 1202 having strands 1270a, 1270 b, and 1270 c, wherein netting 1202 bonded to substrate 1290.The depicted three dimensional netting 1202 is periodically bonded tosubstrate 1290 at a series of bond points 1220 in bond line 1292.Substrate 1290 may be, for example, a polymeric film or a nonwovenfabric, depending on the end use intended for article 1201. Bond lines1292 can be formed by heat or ultrasonic welding, the latter can beaccomplished, for example, with a sonic bonder such as that availableunder the trade designation “OMHZ BRANSON 2000AED” from BransonUltrasonics Corporation, Danbury, Conn.

FIG. 13 is a digital optical image of a front view at 10× of dispensingsurface 1367 of die 1330, specifically the die used in the Example,below). The dispensing surface 1367 has dispensing orifices 1366 a, 1366b, and 1366 c at three different levels in the thickness direction ofthe netting to be produced. (The thickness direction is perpendicular toboth the machine direction and the cross-direction of the extrudedmulti-layer netting.)

FIG. 14 is a digital optical image at 10× of exemplary netting describedherein (and made as described in the Example, below) 1401. Netting 1401includes first strands 1470 a, second strands 1470 b, and thirds strands1470 c.

Portions of the exteriors of the first and second strands bond togetherat the bond regions. In methods described herein for making nettingsdescribed herein, the bonding occurs in a relatively short period oftime (typically less than 1 second). The bond regions, as well as thestrands typically cool through air and natural convection and/orradiation. In selecting polymers for the strands, in some embodiments,it may be desirable to select polymers of bonding strands that havedipole interactions (or H-bonds) or covalent bonds. Bonding betweenstrands has been observed to be improved by increasing the time that thestrands are molten to enable more interaction between polymers. Bondingof polymers has generally been observed to be improved by reducing themolecular weight of at least one polymer and or introducing anadditional co-monomer to improve polymer interaction and/or reduce therate or amount of crystallization. In some embodiments, the bondstrength is greater than the strength of the strands forming the bond.In some embodiments, it may be desirable for the bonds to break and thusthe bonds will be weaker than the strands.

Suitable polymeric materials for extrusion from dies described herein,methods described herein, and for composite layers described hereininclude thermoplastic resins comprising polyolefins (e.g., polypropyleneand polyethylene), polyvinyl chloride, polystyrene, nylons, polyesters(e.g., polyethylene terephthalate) and copolymers and blends thereof.Suitable polymeric materials for extrusion from dies described herein,methods described herein, and for composite layers described herein alsoinclude elastomeric materials (e.g., ABA block copolymers,polyurethanes, polyolefin elastomers, polyurethane elastomers,metallocene polyolefin elastomers, polyamide elastomers, ethylene vinylacetate elastomers, and polyester elastomers). Exemplary adhesives forextrusion from dies described herein, methods described herein, and forcomposite layers described herein include acrylate copolymer pressuresensitive adhesives, rubber based adhesives (e.g., those based onnatural rubber, polyisobutylene, polybutadiene, butyl rubbers, styreneblock copolymer rubbers, etc.), adhesives based on silicone polyureas orsilicone polyoxamides, polyurethane type adhesives, and poly(vinyl ethylether), and copolymers or blends of these. Other desirable materialsinclude, for example, styrene-acrylonitrile, cellulose acetate butyrate,cellulose acetate propionate, cellulose triacetate, polyether sulfone,polymethyl methacrylate, polyurethane, polyester, polycarbonate,polyvinyl chloride, polystyrene, polyethylene naphthalate, copolymers orblends based on naphthalene dicarboxylic acids, polyolefins, polyimides,mixtures and/or combinations thereof. Exemplary release materials forextrusion from dies described herein, methods described herein, and forcomposite layers described herein include silicone-grafted polyolefinssuch as those described in U.S. Pat. No. 6,465,107 (Kelly) and U.S. Pat.No. 3,471,588 (Kanner et al.), silicone block copolymers such as thosedescribed in PCT Publication No. WO96039349, published Dec. 12, 1996,low density polyolefin materials such as those described in U.S. Pat.No. 6,228,449 (Meyer), U.S. Pat. No. 6,348,249 (Meyer), and U.S. Pat.No. 5,948,517 (Meyer), the disclosures of which are incorporated hereinby reference.

In some embodiments, the sheath has at least one of a melting orsoftening point, wherein the core has at least one of a melting orsoftening point, and where the at least one of the melting or softeningpoint of the sheath is lower than at least one of the melting orsoftening point of the core.

In some embodiments, the first polymeric strands have the core of thefirst polymeric material and the sheath of the second, differentpolymeric material, wherein the second polymeric strands have a core ofa third polymeric material and a sheath of a fourth polymeric materialdifferent from the third polymeric material, and wherein at least one of(a) the first polymeric material is different than the third polymericmaterial or (b) the second polymeric material is different than thefourth polymeric material. When one of more of the arrays of strands isconfigured as a core/sheath strand, the polymers forming the core andthe sheath are independently a thermoplastic (e.g., adhesives, nylons,polyesters, polyolefins, polyurethanes, elastomers (e.g., styrenic blockcopolymers), and blends thereof. In some embodiments, the polymerforming the sheath is an adhesive material.

In some embodiments, polymeric materials used to make three-dimensionalpolymeric strand netting described herein may comprise a colorant (e.g.,pigment and/or dye) for functional (e.g., optical effects) and/oraesthetic purposes (e.g., each has different color/shade). Suitablecolorants are those known in the art for use in various polymericmaterials. Exemplary colors imparted by the colorant include white,black, red, pink, orange, yellow, green, aqua, purple, and blue. In someembodiments, it is desirable level to have a certain degree of opacityfor one or more of the polymeric materials. The amount of colorant(s) tobe used in specific embodiments can be readily determined by thoseskilled in the (e.g., to achieve desired color, tone, opacity,transmissivity, etc.). If desired, the polymeric materials may beformulated to have the same or different colors.

Strands made using methods described herein do not substantially crossover each other (i.e., at least 50 (at least 55, 60, 65, 70, 75, 80, 85,90, 95, 99, or even 100) percent by number).

In some embodiments, three-dimensional polymeric strand nettingdescribed herein have a thickness up to 750 micrometers (in someembodiments, up to 500 micrometers, 250 micrometers, 100 micrometers, 75micrometers, 50 micrometers, or even up to 25 micrometers; in a rangefrom 10 micrometers to 750 micrometers, 10 micrometers to 750micrometers, 10 micrometers to 500 micrometers, 10 micrometers to 250micrometers, 10 micrometers to 100 micrometers, 10 micrometers to 75micrometers, 10 micrometers to 50 micrometers, or even 10 micrometers to25 micrometers).

In some embodiments, the polymeric strands have an average width in arange from 10 micrometers to 500 micrometers (in a range from 10micrometers to 400 micrometers, or even 10 micrometers to 250micrometers).

In some embodiments, three-dimensional polymeric strand nettingdescribed herein have a basis weight in a range from 5 g/m² to 400 g/m²(in some embodiments, 10 g/m² to 200 g/m²), for example,three-dimensional polymeric strand netting as-made from dies describedherein. In some embodiments, three-dimensional polymeric strand nettingdescribed herein after being stretched have a basis weight in a rangefrom 0.5 g/m² to 40 g/m² (in some embodiments, 1 g/m² to 20 g/m²).

In some embodiments, three-dimensional polymeric strand nettingdescribed herein have a strand pitch in a range from 0.5 mm to 20 mm (insome embodiments, in a range from 0.5 mm to 10 mm).

It has been observed that when some of the embodiments of netting madeaccording to the present disclosure are stretched, they will relax to alength that is less than their original length before stretching. Whilenot wishing to be bound by theory, it is believed that this is due tocurling of the bond regions within the netting structure.

Optionally, nettings described herein are attached to a backing. Thebackings may be, for example, one of a film, net, or non-woven. Filmsmay be particularly desirable, for example, for applications utilizingclear printing or graphics. Nonwovens or nets may be particularlydesirable, for example, where a softness and quietness that filmstypically do not have is desired. The netting may be stretched andbonded between at least two layers of film or nonwoven where the bondpoints have a plurality (at least two) of bond points that do notinclude the netting in the bond. Alternatively, an unstretched nettingcould be bonded between at least two layers of film or nonwoven wherethe bond points have a plurality (at least two) of bond points that donot include the netting in the bond. These constructions may requiresubsequent stretching, either localized (“ring rolling”) or global, tobecome an activated elastic laminate.

In some embodiments, nettings described herein are elastic. In someembodiments, the polymeric strands have a machine direction and across-machine direction, wherein the netting or arrays of polymericstrands is elastic in machine direction, and inelastic in thecross-machine direction. Elastic means that the material willsubstantially resume its original shape after being stretched (i.e.,will sustain only small permanent set following deformation andrelaxation which set is less than 50 percent (in some embodiments, lessthan 25, 20, or even less than 10 percent) of the original length atmoderate elongation (i.e., about 400-500%; in some embodiments, up to300% to 1200%, or even up to 600 to 800%) elongation at roomtemperature). The elastic material can be both pure elastomers andblends with an elastomeric phase or content that will still exhibitsubstantial elastomeric properties at room temperature.

It is within the scope of the instant disclosure to use heat-shrinkableand non-heat shrinkable elastics. Non-heat shrinkable means that theelastomer, when stretched, will substantially recover sustaining only asmall permanent set as discussed above.

In some embodiments, three-dimensional polymeric strand nettingdescribed herein of alternating first and second polymeric strandsexhibit at least one of diamond-shaped or hexagonal-shaped openings.

In some embodiments, the polymeric strands have an average width in arange from 10 micrometers to 500 micrometers (in a range from 10micrometers to 400 micrometers, or even 10 micrometers to 250micrometers)

In some embodiments, the strands (i.e., the first strands, secondstrands, third strands and bond regions, and other optional strands,each have thicknesses that are substantially the same.

In some embodiments, the bond regions have an average largest dimensionperpendicular to the strand thickness, and wherein the average largestdimension of the bond regions is at least 2 (in some embodiments, atleast 3, 4, 5, 10, or even at least 15) times greater than the averagewidth of at least one of the first strands or the second strands.

In some embodiments, netting described herein includes an array ofengagement posts (e.g., hooks) for engaging with the netting. Engagementhooks can be made as is known in the art (see, for example, U.S. Pat.No. 5,077,870 (Melbye et al.)).

Nettings of polymeric strands described herein have a variety of uses,including wound care and other medical applications (e.g., elasticbandage-like material, surface layer for surgical drapes and gowns, andcast padding), tapes (including for medical applications), filtration,absorbent articles (e.g., diapers and feminine hygiene products) (e.g.,as a layer(s) within the articles and/or as part of an attachment systemfor the articles or elastic components), pest control articles (e.g.,mosquito nettings), geotextile applications (e.g., erosion controltextiles), water/vapor management in clothing, reinforcement fornonwoven articles (e.g., paper towels), self bulking articles (e.g., forpackaging) where the netting thickness is increased by stretchingnettings with first strands have average first yield strength, andwherein the second strands have an average second yield strength that isdifferent (e.g., at least 10 percent different) than the first yieldstrength, floor coverings (e.g., rugs and temporary mats), grip supportsfor tools, athletic articles, breathable elastic wrist and headbands,electrodes in light weight lead acid batteries, and pattern coatedadhesives.

Advantages of some embodiments of nettings described herein when used asa backing, for example, for some tapes and wound dressings can includeconformability, particularly in the cross direction (e.g., at least 50%elongation in the machine direction).

In some embodiments, nettings described herein are made of, or coatedwith, hydrophilic material to make them absorbent. In some embodiments,nettings described herein are useful as wound absorbants to removeexcess exudate from wounds, and in some embodiments, nettings describedherein are made of bioresorbable polymers.

In some filtration applications, the netting can be used, for example,to provide spacers between filtering layers for filtration packs and/orto provide rigidity and support for filtration media. In someembodiments, several layers of the netting are used, where each layer isset to provide optimal filtering. Also, in some embodiments, the elasticfeature of some nettings described herein can facilitate expansion thefilter as the filter fills up.

In some embodiments, nettings described herein have high and low modulusstrands such that stretching netting having a curled bond area cangenerate a lofted, accessible fiber for hook attachment (i.e., for anattachment system). In such oriented nettings attachment loops can havefiber strengths that are greater than unoriented nettings.

In some embodiments, nettings described herein that are elastic can flexin the machine direction, cross direction, or both directions, which canprovide, for example, comfort and fit for diapers. Elastic netting canalso provide a breathable, soft, and flexible attachment mechanism(e.g., elastic netting can be attached to posts that fit through theelastic net, the elastic netting can be made with a ribbon regionsection attached to the netting to provide the fingerlift, the elasticcan be made as elastic in one direction and inelastic in the seconddirection with an elastic and inelastic strand, or the ribbon regionsection can have molded hooks to provide attachment to a loop).

In some embodiments, nettings described herein useful as grip supportsfor tools, athletic articles are made using high friction polymers.

Some embodiments of nettings described herein can be used as or indisposable absorbent articles that may be useful, for example aspersonal absorbent articles for absorbing bodily fluids (e.g.,perspiration, urine, blood, and menses) and disposable household wipesused to clean up similar fluids or typical household spills.

A particular example of a disposable absorbent article comprisingnettings described herein are disposable absorbent garments such asinfant diapers or training pants, products for adult incontinence,feminine hygiene products (e.g., sanitary napkins and panty liners). Atypical disposable absorbent garment of this type is formed as acomposite structure including an absorbent assembly disposed between aliquid permeable bodyside liner and a liquid impermeable outer cover.These components can be combined with other materials and features suchas elastic materials and containment structures to form a product thatis specifically suited to its intended purposes. Feminine hygienetampons are also well known and generally are constructed of anabsorbent assembly and sometimes an outer wrap of a fluid perviousmaterial.

In some embodiments, at least some of strands are electricallyconductive material on an outer surface thereof. In some embodiments, atleast some of the strands are coated with an electrically conductivematerial (e.g., graphite, silver, and nickel), wherein methods formaking netting described herein further comprise applying (e.g.,coating) an electrically conductive material onto at least a portion ofthe outer surface of the netting. In some embodiments, the polymer of atleast some of the strands comprise electrically conductive material(e.g., electrically conductive particles), wherein the electricallyconductive material is added to the polymer before it is processed intothe netting. These electrically conductive nettings can be useful, forexample, as electrodes in light weight lead acid batteries.

Additional information that may be useful in making and using nettingsdescribed therein, when combined with the instant disclosure, can befound in applications having U.S. Ser. Nos. 61/526,001, filed Aug. 22,2011, and 61/530,521, filed Sep. 2, 2011, the disclosures of which areincorporated herein by reference.

Exemplary Embodiments

1A. A three-dimensional polymeric strand netting, wherein a plurality ofthe polymeric strands are periodically joined together in a regularpattern at bond regions throughout the netting, wherein at least some(in some embodiments, a majority by number) of the polymeric strands areperiodically bonded to at least three (four, five, six, or more)adjacent polymeric strands, and wherein no polymeric strands arecontinuously bonded to another polymeric strand.

2A. The three-dimensional polymeric strand netting of Embodiment 1A,wherein the three-dimensional network of polymeric strands has athickness up to 750 micrometers (in some embodiments, up to 500micrometers, 250 micrometers, 100 micrometers, 75 micrometers, 50micrometers, or even up to 25 micrometers; in a range from 10micrometers to 750 micrometers, 10 micrometers to 750 micrometers, 10micrometers to 500 micrometers, 10 micrometers to 250 micrometers, 10micrometers to 100 micrometers, 10 micrometers to 75 micrometers, 10micrometers to 50 micrometers, or even 10 micrometers to 25micrometers).

3A. The three-dimensional polymeric strand netting of either Embodiment1A or 2A having a basis weight in a range from 5 g/m² to 400 g/m² (insome embodiments, 10 g/m² to 200 g/m²).

4A. The three-dimensional polymeric strand netting of a eitherEmbodiment 1A or 2A having a basis weight in a range from 0.5 g/m² to 40g/m² (in some embodiments, 1 g/m² to 20 g/m²).

5A. The three-dimensional polymeric strand netting of any precedingEmbodiment having a strand pitch in a range from 0.5 mm to 20 mm (insome embodiments, in a range from 0.5 mm to 10 mm).

6A. The three-dimensional polymeric strand netting of any precedingEmbodiment that is elastic.

7A. The three-dimensional polymeric strand netting of any of Embodiments1A to 6A having a machine direction and a cross-machine direction, andbeing elastic in machine direction, and inelastic in the cross-machinedirection.

8A. The three-dimensional polymeric strand netting of any of Embodiments1A to 7A having a machine direction and a cross-machine direction,wherein the netting is inelastic in machine direction, and elastic inthe cross-machine direction.

9A. The three-dimensional polymeric strand netting of any precedingEmbodiment, wherein at least some of the polymeric stands include atleast one of a dye or pigment therein.

10A. The three-dimensional polymeric strand netting of any precedingEmbodiment that exhibits at least one of diamond-shaped orhexagonal-shaped openings.

11A. The three-dimensional polymeric strand netting of any precedingEmbodiment, wherein at least some of the polymeric strands comprise afirst polymer that is a thermoplastic (e.g., adhesives, nylons,polyesters, polyolefins, polyurethanes, elastomers (e.g., styrenic blockcopolymers), and blends thereof).

12A. The three-dimensional polymeric strand netting of Embodiment 11A,wherein the first polymer is an adhesive material.

13A. The three-dimensional polymeric strand netting of any precedingEmbodiment, wherein the plurality of strands include alternating firstand second polymeric strands, wherein the second polymeric strandscomprise a second polymer.

14A. The three-dimensional polymeric strand netting of Embodiment 13A,wherein the wherein the first polymeric strands comprise the firstpolymer, and wherein the second polymeric strands comprise a secondpolymer that is a thermoplastic (e.g., adhesives, nylons, polyesters,polyolefins, polyurethanes, elastomers (e.g., styrenic blockcopolymers), and blends thereof).

15A. The three-dimensional polymeric strand netting of any ofEmbodiments 11A to 14A further comprising third strands disposed betweenat least some of the alternating first and second strands.

16A. The three-dimensional polymeric strand netting of any ofEmbodiments 1A to 10A, wherein at least a plurality (i.e., at least two)of the polymeric strands have a core of a first polymeric material and asheath of a second, different polymeric material.

17A. The three-dimensional polymeric strand netting of any precedingEmbodiment, wherein the sheath has at least one of a melting orsoftening point, wherein the core has at least one of a melting orsoftening point, and where the at least one of the melting or softeningpoint of the sheath is lower than at least one of the melting orsoftening point of the core.

18A. The three-dimensional polymeric strand netting of either Embodiment16A or 17A, wherein at least some of the cores have at least two (insome embodiments at least 3 or more) sheaths.

19A. The three-dimensional polymeric strand netting of Embodiment 16A to18A having a negative permanent set.

20A. The three-dimensional polymeric strand netting of any ofEmbodiments 1A to 19A, wherein the polymeric strands have an averagewidth in a range from 10 micrometers to 500 micrometers (in a range from10 micrometers to 400 micrometers, or even 10 micrometers to 250micrometers).

21A. The three-dimensional polymeric strand netting of any precedingEmbodiment that is stretched.

22A. The three-dimensional polymeric strand netting of any precedingEmbodiment, wherein at least some of strands are electricallyconductive.

23A. The three-dimensional polymeric strand netting of Embodiment 22A,wherein at least some of the strands are coated with an electricallyconductive material.

24A. The three-dimensional polymeric strand netting of either Embodiment22A or 23A, wherein at least some of the strands comprise electricallyconductive material.

25A. An article comprising a backing having the three-dimensionalpolymeric strand netting of any preceding Embodiment on a major surfacethereof.

26A. The article of Embodiment 25A, wherein the backing is one of afilm, net, or non-woven.

27A. The article of Embodiment 26A that includes bond lines.

28A. An article comprising the three-dimensional polymeric strandnetting of any of Embodiment 1A to 24A disposed between two non-wovenlayers.

29A. An article of any of Embodiments 1A to 24A comprising two of thethree-dimensional polymeric strand netting with a ribbon region disposedthere between.

30A. The article of Embodiment 29A, wherein the three-dimensionalpolymeric strand netting and ribbon region are integral.

31A. The article of either Embodiment 29A or 30A, wherein the ribbonregion has a major surface with engagement posts thereon.

32A. An article comprising the three-dimensional polymeric strandnetting of any of Embodiments 1A to 24A disposed between two ribbonregions.

33A. The article of Embodiment 32A, wherein the three-dimensionalpolymeric strand netting is integral with each of the ribbon regions.

34A. The article of either Embodiment 32A or 33A, wherein the film has amajor surface with engagement posts thereon.

35A. An attachment system comprising the three-dimensional polymericstrand netting of any of Embodiments 1A to 24A and an array ofengagement posts (e.g., hooks) for engaging with the three-dimensionalnetwork of polymeric strands.

36A. An absorbent article comprising the attachment system of Embodiment33A.

37A. A method of making the three-dimensional polymeric strand nettingof any of Embodiments 1A to 24A, the method comprising:

providing an extrusion die comprising a plurality of shims positionedadjacent to one another, the shims together defining at least a firstcavity (in some embodiments, a second cavity, a third cavity, and/ormore cavities) and a dispensing surface, wherein the dispensing surfacehas a first array of first dispensing orifices and a second array ofsecond dispensing orifices positioned adjacent to each other,alternating with a third array of third dispensing orifices, wherein theplurality of shims comprises a plurality of a repeating sequence ofshims, wherein the repeating sequence comprises a shim that provides afluid passageway between a cavity and one of the first dispensingorifices, a shim that provides a fluid passageway between a cavity andone of the second dispensing orifices, and a shim that provides a fluidpassageway between a cavity and one of the third dispensing orifices;and

dispensing polymeric strands from at least one of the first, second, orthird arrays of dispensing orifices at a first strand speed whilesimultaneously dispensing polymeric strands from at least one of theother arrays at a second strand speed, wherein the first strand speed isat least 2 (in some embodiments, in a range from 2 to 6, or even 2 to 4)times the second strand speed to provide the three-dimensional nettingdispensing polymeric strands from at least one of the first, second, orthird arrays of dispensing orifices at a first strand speed whilesimultaneously dispensing polymeric strands from at least one of theother arrays at a second strand speed, wherein the first strand speed isat least 2 (in some embodiments, in a range from 2 to 6, or even 2 to 4)times the second strand speed to provide the three-dimensional netting.

1B. An extrusion die comprising a plurality of shims positioned adjacentto one another, the shims together defining at least a first cavity anda dispensing surface, wherein the dispensing surface has a first arrayof first dispensing orifices, a second array of second dispensingorifices, and a third array of third dispensing orifices, the thirdarray being disposed generally between the first and second arrays;wherein the plurality of shims comprises a plurality of a repeatingsequence of shims, wherein the repeating sequence comprises a shim thatprovides a fluid passageway between a cavity and one of the firstdispensing orifices, a shim that provides a fluid passageway between acavity and one of the second dispensing orifices, and a shim thatprovides a fluid passageway between a cavity and one of the thirddispensing orifices.

2B. The extrusion die of Embodiment 1B, wherein the repeating sequencefurther comprises at least one spacer shim.

3B. The extrusion die of any of either Embodiments 1B or 2B, wherein thedispensing orifices of each respective array are collinear.

4B. The extrusion die of Embodiment 3B, wherein the third array isoffset from the first and second arrays.

5B. The extrusion die of any of Embodiments 1B to 4B further comprisinga manifold body for supporting the shims, the manifold body having atleast one manifold therein, the manifold having an outlet; and furthercomprising an expansion seal disposed so as to seal the manifold bodyand the shims, wherein the expansion seal defines a portion of thecavity, and wherein the expansion seal allows a conduit between themanifold and the cavity.

6B. The extrusion die of Embodiment 5B, wherein the shims define asecond cavity, and the expansion seal defines a portion of both thefirst and the second cavities.

7B. The extrusion die of any of Embodiments 1B to 6B, wherein each ofthe dispensing orifices of the first and the second and third arrayshave a width, and wherein each of the dispensing orifices of the first,second, and third arrays are spaced apart by at least twice the width ofthe respective dispensing orifice.

8B. The extrusion die of Embodiments 1B to 7B, wherein each orifice hasa height, and wherein the arrays of orifices are offset by an amount ofspacing not greater than the height of adjacent orifices.

9B. The extrusion die of any of Embodiments 1B to 8B, wherein the firstarray is supplied with molten polymer from a cavity so as to dispensethe polymer from the first array; the second array is supplied withmolten polymer from a cavity so as to dispense the polymer from thesecond array at the first strand speed; and wherein the third array issupplied with molten polymer from a cavity so as to dispense the polymerfrom the second array at a second strand speed; and wherein the firststrand speed differs from the second strand speed differs by a factor ofat least 2 (in some embodiments in a range from 2 to 6, or even 2 to 4)times the second strand speed, such that a netting comprising an arrayof alternating first and second polymeric strands is formed.

10B. The extrusion die of any of Embodiments 1B to 9B, wherein the fluidpassageway is up to 5 mm in length.

11B. The extrusion die of any of Embodiments 1B to 10B, wherein theshims further define at least a second cavity, wherein the repeatingsequence of shims provide a fluid passageway from both the first andsecond cavities to one of the arrays, and wherein the first cavity issupplied with a first polymer and the second cavity is supplied with asecond polymer so as to dispense two-component strands from that array.

12B. The extrusion die of Embodiment 11B wherein the two-componentstrand has a core/sheath arrangement.

Advantages and embodiments of this invention are further illustrated bythe following examples, but the particular materials and amounts thereofrecited in these examples, as well as other conditions and details,should not be construed to unduly limit this invention. All parts andpercentages are by weight unless otherwise indicated.

Example

A co-extrusion die as generally depicted in FIG. 9, with 3 cavities,with a 4 shim repeating pattern of extrusion orifices as generallyillustrated in FIGS. 7 and 8, was prepared. The thickness of each shimwas 4 mils (102 mm). The shims were formed from stainless steel, withperforations cut by a wire electron discharge machining. The height ofthe first and third extrusion orifice was cut to 5 mils (0.127 mm). Thefirst and third extrusion orifices were cut into the same shim at aspacing of 10 mils (0.254 mm) between orifice edges as generallyillustrated in FIGS. 5 and 6. The height of the second set of extrusionorifices was cut to 10 mils (0.254 mm) as generally illustrated in FIGS.2 and 3. The extrusion orifices were aligned in a collinear, alternatingarrangement as shown in FIG. 13 below, such that the second extrusionorifice was centered between the first and third orifices. The totalwidth of the shim setup was 10 cm.

The inlet fittings on the two end blocks were each connected to aconventional single-screw extruder. The first and third extrusion cavitywere connected together to the same extruder. A chill roll waspositioned adjacent to the distal opening of the coextrusion die toreceive the extruded material. The extruder feeding the first and thirdcavity was loaded with thirty-five melt flow index polypropylene pellets(obtained under the trade designation “EXXONMOBIL 3155 PP” fromExxonMobil, Irving Tex.).

The extruder feeding the second cavity was loaded with thirty five meltflow index polypropylene pellets (obtained under the trade designation“EXXONMOBL 3155 PP” from ExxonMobil). Other process conditions arelisted below:

First orifice width: 0.102 mm First orifice height: 0.127 mm Secondorifice width: 0.102 mm Second orifice height: 0.254 mm Third orificewidth 0.102 mm Third orifice height: 0.127 mm Ratio of orifice height towidth for oscillating strands 1.25:1 Land spacing between orifices 0.102mm Flow rate of first and third orifice polymer 0.68 kg/hr. Flow rate ofsecond orifice polymer 0.18 kg/hr. Extrusion temperature 193° C. Quenchroll temperature 15° C. Quench takeaway speed 4.6 m/min.

Using an optical microscope, the three-dimensional polymeric strandnetting dimensions were measured and are shown below.

Netting thickness 0.18 mm Netting basis weight 40 grams Bond length inthe machine direction 1.0 mm Netting bonding distance in the machinedirection (pitch) 4.5 mm First polymer strand width 0.08 mm Secondpolymer strand width 0.05 mm

The resulting three-dimensional polymeric strand netting had first tosecond strand cross-sections with a cross sectional area ratio of 1:2.An optical photograph of the three-dimensional polymeric strand nettingis shown in FIG. 14.

Foreseeable modifications and alterations of this disclosure will beapparent to those skilled in the art without departing from the scopeand spirit of this invention. This invention should not be restricted tothe embodiments that are set forth in this application for illustrativepurposes.

What is claimed is:
 1. A method of making a three-dimensional polymericstrand netting, wherein a plurality of the polymeric strands areperiodically joined together in a regular pattern at bond regionsthroughout the netting, wherein at least some of the polymeric strandsare periodically bonded to at least three adjacent polymeric strands,and wherein no polymeric strands are continuously bonded to anotherpolymeric strand, the method comprising: providing an extrusion die,comprising: a plurality of shims positioned adjacent to one another, theshims together defining at least a first cavity supplied with a firstpolymer, and a second cavity supplied with a second polymer differentfrom the first polymer, wherein at least one of the first and the secondpolymers comprises a thermoplastic chosen from adhesives, nylons,polyesters, polyolefins, polyurethanes, styrenic block copolymers, andblends thereof, and a dispensing surface, wherein the dispensing surfacecomprises a first array of first dispensing orifices and a second arrayof second dispensing orifices positioned adjacent to each other,alternating with a third array of third dispensing orifices, wherein theplurality of shims comprises a plurality of a repeating sequence ofshims, wherein the repeating sequence of shims comprises a shim thatprovides a fluid passageway between at least one of the first and thesecond cavities and one of the first dispensing orifices, a shim thatprovides a fluid passageway between at least one of the first and thesecond cavities and one of the second dispensing orifices, and a shimthat provides a fluid passageway between at least one of the first andthe second cavities and one of the third dispensing orifices; anddispensing polymeric strands from at least one of the first, second, orthird arrays of dispensing orifices to provide the three-dimensionalnetting, wherein at least some of the polymeric strands in thethree-dimensional netting are formed from the first polymer and at leastsome of the polymeric strands in the three-dimensional netting areformed from the second polymer, and wherein the first and the seconddispensing orifices are configured such that at least some of thepolymeric strands in the three-dimensional netting have a core of thefirst polymer and a sheath of the second polymer.
 2. The method of claim1, wherein shims together further define a third cavity supplied with athird polymer different from the first polymer and the second polymer,wherein the repeating sequence of shims comprises a shim that provides afluid passageway between at least one of the first, the second and thethird cavities and one of the first dispensing orifices, a shim thatprovides a fluid passageway between at least one of the first, thesecond and the third cavities and one of the second dispensing orifices,and a shim that provides a fluid passageway between at least one of thefirst, the second and the third cavities and one of the third dispensingorifices; and wherein at least some of the polymeric strands in thethree-dimensional netting are formed from the first polymer, at leastsome of the polymeric strands in the three-dimensional netting areformed from the second polymer, and at least some of the polymericstrands in the three-dimensional netting are formed from the thirdpolymer.
 3. The method of claim 1, comprising dispensing the firstpolymer from at least one of the arrays of dispensing orifices at afirst strand speed while simultaneously dispensing the second polymerfrom at least one of the other arrays of dispensing orifices at a secondstrand speed, wherein the first strand speed is at least 2 times thesecond strand speed.
 4. The method of claim 1, wherein the repeatingsequence of shims comprises at least 4 shims.
 5. The method of claim 4,wherein the repeating sequence of shims comprises at least one spacershim.
 6. The method of claim 1, wherein the dispensing orifices of eachrespective array are collinear.
 7. The method of claim 1, wherein thethird array is offset from the first and second arrays.
 8. The method ofclaim 1, wherein each of the dispensing orifices of the first and thesecond and third arrays have a width, and wherein each of the dispensingorifices of the first, second, and third arrays are spaced apart by atleast twice the width of the respective dispensing orifice.
 9. Themethod of claim 1, wherein each orifice has a height, and wherein thearrays of orifices are offset by an amount of spacing not greater thanthe height of adjacent orifices.